Abstract
Industrial wastewater sometimes contains a lot of sulfate or is neutralized by sulfuric acid. The effects of sulfate on methane fermentation were monitored in a fixed-bed anaerobic reactor by gradual increase of sulfate in influent wastewater.
Even at high sulfate concentration of 20000mg/l in influent water, continuous treatability test showed no inhibition to the TOC removal with more than 95% at TOC loading rate of 3 kg/m3·d.
The result was attributed to the facts that sulfate did not inhibit methanogenesis and that subject to the ratio of sulfur and carbon in the liquid, hydrogen sulfide did not increase in proportion to the increase of sulfate in influent water. Besides, keeping pH of the liquid at around 7 was another factor to maintain the unionized hydrogen sulfide at a low level.
